Nomenclature Family names cited with two dates (the second one in parentheses) are those ruled by Article 40(2) of ICZN. "If ... a family-group name was replaced before 1961 because of the synonymy of the type genus, the replacement name is to be maintained if it is in prevailing usage. A name maintained by virtue of this Article retains its own author [and date, the first date cited] but takes the priority of the replaced name [the date cited in parentheses, here alluding to Isocardiidae] [details]